In a mobile communication device and the like, a high-frequency switch for switching a high-frequency terminal to an antenna for transmission or to an antenna for reception is used. As the high-frequency switch, a semiconductor switch having an insulated gate field-effect transistor (a MOS transistor) can be used.
Providing the semiconductor switch on a silicon-on-insulator (SOI) substrate in which a semiconductor layer is provided on an insulating film over a semiconductor substrate is effective because the use of a high-resistance semiconductor substrate reduces the parasitic capacitance between a high-frequency circuit and the semiconductor substrate and may improve operating speed of the semiconductor switch.
However, harmonic distortions sometimes occur in the semiconductor switch provided on a SOI substrate due to the high-frequency signal.